package com.example.day07;

public class StringDemo {
    public static void main(String[] args) {

//        String a=new String("abc");
//        a="bb";
//        System.out.println(a.length());
//        //contains 判断括号内的字符串是否在该字符串中
//        a.contains("aa");

        String  a="abcd";
        a+="ok";
    }
}
